Tagged Questions
2
votes
0answers
127 views
Field content and symmetry groups of Minimal Composite Higgs Models
I'm trying to teach myself the Composite Higgs Model, both its theory and its LHC phenomenology (particularly the 4DCHM). Unfortunately, I'm struggling; the literature is contradictory and/or omits ...
5
votes
1answer
113 views
What is the first appearance of the MV (McLerran-Venugopalan) initial condition?
First a quick introduction for the unfamiliar: in saturation physics (my research field), a lot of theoretical work centers on the BK (Balitsky-Kovchegov) equation, which is a differential equation ...
7
votes
1answer
141 views
Parton showering in Pythia 6 Monte Carlo generator
I have Pythia Monte Carlo (MC) samples where I can't understand the parton showering model. If I print out full decay chains from the events, each event contains multiple string objects with pdgId 92. ...
4
votes
1answer
587 views
What is the relationship between string net theory and string / M-theory?
I've just learned from this one of Prof. Wen's answers that there exists a theory called string net theory. Since I've never heard about this before it picks my curiosity, so I`d like to ask some ...
15
votes
3answers
891 views
Are elementary particles actually more elementary than quasiparticles?
Quarks and leptons are considered elementary particles, while phonons, holes, and solitons are quasiparticles.
In light of emergent phenomena, such as fractionally charged particles in fractional ...
26
votes
0answers
509 views
What is the upper-limit on intrinsic heating due to dark matter?
Cold dark matter is thought to fill our galactic neighborhood with a density $\rho$ of about 0.3 GeV/cm${}^3$ and with a velocity $v$ of roughly 200 to 300 km/s. (The velocity dispersion is much ...
4
votes
1answer
69 views
Colour decomposition of $n-$gluon tree amplitude
I have here a $SU(N_c)$ Yang-Mill's theory and let the index $i$, label the $n$-gluons, and $\{k_i, \lambda_i, a_i\}$ be its momenta, helicity and colour index and $\cal{A}_n^{tree/1-loop}(\{k_i, ...
9
votes
1answer
168 views
Derivation of the effective potential between a quark and an anti-quark
Typically in particle physics books (not in QFT books!) I have often seen this statement that the potential between a heavy quark and its anti-quark can be "empirically" represented as $V(r) = ...
3
votes
1answer
46 views
Physics in high lepton chemical potential
I consider zero temperature and high lepton number chemical potential $\mu$. This results in a neutrino (or antineutrino, depending on the sign of the potential) "sea" filling a Fermi sphere in ...
4
votes
0answers
104 views
Is there precision experimental evidence for Furry's theorem — that only even degree VEVs are non-zero?
Is there precision experimental evidence for or contradicting Furry's theorem -- that only even degree VEVs are non-zero, specifically for the EM field?
6
votes
1answer
96 views
Status of the little hierarchy problem
What is the current thinking on the little hierarchy problem in light of a potential Higgs mass above 120 GeV? A few years ago, at least, I remember various phenomenologists saying that this at least ...
11
votes
1answer
88 views
Higgs Field - Is its discovery truly “around the corner”?
Rather surprised I haven't seen many questions or discussion regarding the rumored confirmation of the Higgs field. As I understand it, the energies where they saw things were actually quite a bit ...
12
votes
5answers
305 views
Does Kaluza-Klein theory successfully unify GR and EM? Why can't it be extended to the Standard Model gauge group?
As a quick disclaimer, I thought this might be a better place to ask than Physics.SE. I already searched there with "kaluza" and "klein" keywords to find an answer, but without luck. As background, ...
8
votes
1answer
53 views
Superconformal Multiplet Calculus in 6D
A convenient method for dealing with off-shell formulations of
supergravity theories is provided by the superconformal multiplet
calculus. This calculus was originally constructed for 4d ${\cal N}=2$
...
4
votes
0answers
23 views
Classic mass predictions from Left-Right models with discrete symmetries?
I am covering the classic literature on predictions of Cabibbo angle or other relationships in the mass matrix. As you may remember, this research was a rage in the late seventies, after noticing that ...
6
votes
1answer
43 views
Which arguments for $m_u \approx 0$ are still in the market?
The RPP note on quarks masses has traditionally carried, and it is still there, the comment that
It is particularly important to determine the quark mass ratio mu/md,
since there is no strong CP ...
6
votes
0answers
20 views
status of +4/3 scalar as explanation of $t\bar t$ asymmetry
One of the early proposals for the Tevatron asymmetry on $t \bar t$ was a "fundamental diquark" with a charge (and hypercharge) +4/3, either in a triplet or a sextet colour. I am interested on the ...
17
votes
3answers
105 views
Twistors in Curved Spacetime
I am looking for good and recent references to constructing twistor space for curved spacetime. This could be a general spacetime, or specific ones (say maximally symmetric spaces different from ...
5
votes
1answer
100 views
Do Killing spinors know global information?
The conformal Killing spinor equations on $R\times S^3$ in Minkowski signature are
\begin{equation}
\nabla_\mu \epsilon=\pm \frac{i}{2}\gamma_\mu\gamma^0\gamma^5\epsilon
\end{equation}
whose solution ...
13
votes
1answer
95 views
realization of: CFT generating fuction = AdS partition function
An important aspect of the AdS/CFT correspondence is the recipe to compute correlation functions of a boundary operator $\mathcal{O} $ in terms of the supergravity fields in the interior of the ...
19
votes
1answer
67 views
Any use for $F_4$ in hep-th?
In high energy physics, the use of the classical Lie groups are common place, and in the Grand Unification the use of $E_{6,7,8}$ is also common place.
In string theory $G_2$ is sometimes utilized, ...
13
votes
1answer
44 views
Instanton Moduli Space with a Surface Operator
I would like to understand the mathematical language which is relevant to instanton moduli space with a surface operator.
Alday and Tachikawa stated in 1005.4469 that the following moduli spaces are ...
7
votes
1answer
34 views
Are lens spaces classified via a Weinberg angle?
I am thinking about Kaluza Klein theory in the 3 dimensional lens spaces. These have an isometry group SU(2)xU(1), generically, and in some way interpolate between the extreme cases of manifolds $S^2 ...
9
votes
1answer
30 views
Dual Pairs in Four Dimensions
Following the conversation here, I am wondering if anyone knows of an example of dual pair with 4-dimensional N=1 SUSY which relates a non-Abelian gauge theory on one side to a theory with a ...
31
votes
5answers
146 views
Models of neutrinos consistent with OPERA's results
I guess by now most people have heard about the new paper (arXiv:1109.4897) by the OPERA collaboration which claims to have observed superluminal neutrinos with 6$\sigma$ significance. Obviously this ...
41
votes
4answers
3k views
Gauge symmetry is not a symmetry?
I have read before in one of Seiberg's articles something like, that gauge symmetry is not a symmetry but a redundancy in our description, by introducing fake degrees of freedom to facilitate ...
